1. Field of the Invention
The present invention relates generally to the field of semiconductor manufacturing. More specifically, the present invention relates to methods for cleaning a process chamber by photo-assisted chemical cleaning or laser ablation.
2. Description of the Related Art
An important way to improve quality and overall efficiency in fabricating devices is to clean the chamber effectively and economically. During processing, reactive gases released inside the process chamber form layers such as silicon oxides or nitrides on the surface of a substrate being processed. Undesirable deposition occurs elsewhere in the process apparatus, for example, in the area between the gas mixing box and gas distribution manifold. Undesired residues also may be deposited in or around the exhaust channel, the liners and walls of the process chamber during such processes.
Over time, failure to clean the residue from the process apparatus often results in degraded, unreliable processes and defective substrates. Without frequent cleaning procedures, impurities from the residue built up in the process apparatus can migrate onto the substrate. The problem of impurities causing damage to the devices on the substrate is of particular concern with today""s increasingly small device dimensions. Thus, process system maintenance is important for the smooth operation of substrate processing, as well as for improved device yield and better product performance.
Frequently, periodic chamber cleaning between processing of every Nth substrate is desired to improve process system performance in producing high quality devices. Providing an efficient, non-damaging cleaning of the chamber and/or substrate can enhance performance and quality of the devices produced. Two methods of cleaning a process chamber in the art are in situ cleaning (also known as dry-etch cleaning) and wet cleaning. In an in-situ cleaning operation, process gases are evacuated from the process chamber and one or more cleaning gases are introduced. Energy is then applied to promote a reaction between the gases and any residues that may have accumulated on the process chamber""s interior surfaces. Residues on the process chamber""s interior react with the cleaning gases, forming gaseous by-products that are then exhausted from the process chamber, along with non-reacted portions of the cleaning gases. The cleaning process is followed by the resumption of normal processing.
In contrast to an in situ cleaning procedure, in which the process chamber remains sealed, a wet cleaning procedure is performed by breaking the process chamber""s vacuum seal and manually wiping down the chamber""s interior surfaces. A wet cleaning procedure is normally performed to remove residues that are not entirely removed by the in situ cleaning process, and thus slowly accumulate over time. A solvent is sometimes used to dissolve these residues. Once cleaned, the process chamber is sealed and normal processing is resumed.
Unfortunately, such cleaning operations affect a substrate process system""s throughput in a variety of ways. For example, system throughput is reduced by the time involved in performing cleaning operations. In an in situ cleaning process, time is spent evacuating process gases from, and introducing/evacuating the cleaning gases into/from the process chamber. Flow rates, plasma power levels, temperature, pressure, and other cleaning process conditions must also be reset to desired levels after the cleaning process is completed. When a wet clean is performed, opening the process chamber and physically wiping the chamber""s interior surfaces results in even more downtime because the process must subsequently be re-stabilized. It is thus desirable to reduce the frequency with which such cleaning operations are performed.
Additionally, frequent cleaning operations tend to increase wear on the process chamber components. For example, in-situ cleaning is typically performed using fluoridated carbons (e.g., CF.sub.4, C.sub.2F.sub.6 and the like) or similar fluorine-containing gases (e.g., NF.sub.3 and the like) due to their highly reactive nature. Unfortunately, exposure to plasmas created from such gases often causes the deterioration of process chamber components. This increased wear can lead to component failure, thereby causing extended downtime, and adversely affecting process system throughput.
The use of reactive gases in cleaning process chambers, however, also suffers from a further disadvantage. The same species that provide desirable cleaning characteristics may themselves cause the formation of residues. For example, the use of such gases can cause the accumulation of polymer residues, which also exhibit undesirable qualities. The addition of oxygen to the cleaning process gas may reduce the formation of such polymer residues. In particular, ozone or an oxygen/ozone mixture may provide the desired reduction in polymer formation while speeding the cleaning process, due to ozone""s greater reactivity.
Another example of residues generated by cleaning gases are the cleaning residues often formed by the use of fluoridated compounds in certain cleaning processes. These compounds may react with the aluminum or anodized aluminum which makes up many of the standard process chamber""s components to form an aluminum fluoride residue on the interior surfaces of the chamber and the chamber""s components. The reaction between the aluminum and the fluorine-containing compounds often occurs because the residues within the process chamber vary in thickness and therefore have different cleaning times. Thus, certain areas of the process chamber""s interior may become residue-free (i.e., exposed) before others, resulting in the formation of an aluminum fluoride residue on the exposed portions of the chamber""s interior.
Therefore, the prior art is deficient in the lack of effective means of cleaning a process chamber or process chamber parts Specifically, the prior art is deficient in the lack of effective means of photo-assisted chemical cleaning of a process chamber or of laser ablation cleaning of a process chamber parts. The present invention fulfills these long-standing needs and desires in the art.
One embodiment of the present invention is a method for cleaning a process chamber, comprising the steps of introducing at least one cleaning gas to the process chamber via a section connected to the process chamber; and applying at least one high power density light beam to the section or to the process chamber, wherein the high power density light beam(s) assists dissociation of the cleaning gas in either the section or the process chamber, thereby achieving cleaning activity of the cleaning gas in the process chamber.
Another embodiment of the present invention provides a method for cleaning a process chamber, comprising the steps of introducing at least one halogen-containing cleaning gas to the process chamber via a section connected to the process chamber; and applying at least one high power density light beam comprising an incoherent light beam or a laser light beam to the section or to the process chamber, wherein the high power density light beam(s) assists dissociation of the halogen-containing cleaning gas in either the section or the process chamber, thereby achieving cleaning activity of the halogen-containing cleaning gas in the process chamber.
Yet another embodiment of the present invention is a method for cleaning a process chamber, comprising the steps of introducing at least one fluorine-containing cleaning gas to the process chamber via a section connected to the process chamber; and applying at least one high power density laser beam having a wavelength range from about 190 nm to about 10 xcexcm and an energy density range from about 1 W/mm2 to about 2 MW/mm2 to the section or to the process chamber, wherein the high power density laser beam(s) assists dissociation of the fluorine-containing cleaning gas in either the section or the process chamber, thereby achieving cleaning activity of the fluorine-containing cleaning gas in the process chamber.
Another embodiment of the present invention is a method for cleaning a process chamber, comprising the steps of introducing at least one precursor gas to the process chamber via a section connected to the chamber; applying at least one high power density light beam to the section or directly to the process chamber; and applying a plasma to the process chamber, wherein the plasma activates the precursor gas to generate reactive species, and wherein the high power density light beam(s) assists dissociation of the reactive species, thereby cleaning the process chamber.
Yet another embodiment of the present invention is a method for cleaning a process chamber, comprising the steps of introducing at least one halogen-containing precursor gas to the process chamber via a section connected to the process chamber; applying at least one high power density light beam comprising an incoherent light beam or a laser light beam to the section or directly to the process chamber; and applying a plasma to the process chamber, wherein the plasma activates the precursor gas to generate reactive species, and wherein the high power density light beam(s) assists dissociation of the reactive species, thereby cleaning the process chamber.
Yet another embodiment of the present invention is a method for cleaning a process chamber, comprising the steps of introducing at least one fluorine-containing precursor gas to the process chamber via a section connected to the process chamber; applying at least one high power density laser beam having a wavelength range from about 190 nm to about 10 xcexcm and an energy density range from about 1 W/mm2 to about 2 MW/mm2 to the section or directly to the process chamber; and applying a plasma to the process chamber, wherein the plasma activates the fluorine-containing precursor gas to generate reactive species, and wherein the high power density laser beam(s) assists dissociation of the reactive species, thereby cleaning the process chamber.
Yet another embodiment of the present invention is a method for cleaning a process chamber, comprising the steps of introducing at least one precursor gas to a remote chamber, wherein the remote chamber is connected to the interior of the process chamber; activating the precursor gas in the remote chamber to generate reactive species; introducing the reactive species to the process chamber via a section connected to the chamber; and applying at least one high power density light beam to the section, wherein the high power density light beam(s) assists dissociation of the reactive species, thereby cleaning the process chamber.
In yet another embodiment of the present invention there is provided a method for cleaning a process chamber, comprising the steps of introducing at least one halogen-containing precursor gas to a remote chamber, wherein the remote chamber is connected to the interior of the process chamber; activating the halogen-containing precursor gas in the remote chamber to generate reactive species; introducing the reactive species to the process chamber via a section connected to the chamber; and applying at least one high power density light beam comprising an incoherent light beam or a laser light beam to the section, wherein the high power density light beam(s) assists dissociation of the reactive species, thereby cleaning the process chamber.
In yet another embodiment of the present invention there is provided a method for cleaning a process chamber, comprising the steps of introducing at least one fluorine-containing precursor gas to a remote chamber, wherein the remote chamber is connected to the interior of the process chamber; activating the fluorine-containing precursor gas in the remote chamber to generate reactive species; introducing the reactive species to the process chamber via a section connected to the chamber; and applying at least one high power density laser beam having a wavelength range from about 190 nm to about 10 xcexcm and an energy density range from about 1 W/mm2 to about 2 MW/mm2 to the section, wherein the high power density laser beam(s) assists dissociation of the reactive species, thereby cleaning the process chamber.
In yet another embodiment of the present invention there is provided a method for cleaning a process chamber, comprising the steps of irradiating at least one laser beam to the interior of the process chamber, wherein the laser beam(s) ablates residues from the process chamber; and removing the process residues from the process chamber by at least one carrier gas, thereby cleaning the process chamber.
In yet another embodiment of the present invention there is provided a method for cleaning a process chamber, comprising the steps of irradiating at least one laser beam having a wavelength range from about 190 nm to about 10 xcexcm and an energy density range from about 1 W/mm2 to about 2 MW/mm2 to the interior of the process chamber, wherein the laser beam(s) ablates residues from the process chamber; and removing the process residues from the process chamber by at least one carrier gas, thereby cleaning the process chamber.
Other and further aspects, features, and advantages of the present invention will be apparent from the following description of the embodiments of the invention given for the purpose of disclosure.